[E1000-devel] recvmsg tx timestamp failed: Resource temporarily unavailable

[Gert-Jan R. <gjr...@on...>]

We are using the igb network driver on a linux system with a 82576 
network chip.
The system works good with ptp4l, but if there is data activity on the 
ethernet connection sometimes
ptp4l will log:

Mar 21 18:07:41 OpenWrt user.err ptp4l: [1534.888] recvmsg tx timestamp 
failed: Resource temporarily unavailable
Mar 21 18:07:41 OpenWrt user.err ptp4l: [1534.889] port 1: send delay 
request failed
Mar 21 18:07:41 OpenWrt user.notice ptp4l: [1534.889] port 1: SLAVE to 
FAULTY on FAULT_DETECTED

And will start to resync again sometime later.

Mar 21 18:07:57 OpenWrt user.notice ptp4l: [1550.909] port 1: FAULTY to 
LISTENING on FAULT_CLEARED
Mar 21 18:07:58 OpenWrt user.notice ptp4l: [1551.790] port 1: new 
foreign master 00a069.fffe.0b4969-1

This will happen quite regularly.

I have looked this up in the driver and it seems that recvmsg is 
returning EAGAIN constantly. (It is retrying 100 times)

This behavior makes ptp unusable on our system.
Is anyone aware of this problem or has a pointer to a solution?

Thanks,
     Gert-Jan